The present invention pertains to a support for pipelines for cold liquids with a two-part or more than two-part carriage, which surrounds an insulating shell surrounding the pipeline, wherein the carriage comprises carriage parts connected to one another at connection flanges. Furthermore, the present invention pertains to a process for mounting or supporting such a support.
Such a support is shown, e.g., in Arbeitsblatt Q 03 of the Arbeitsgemeinschaft Industriebau e.V. (AGI) and will be briefly explained below on the basis of FIG. 15. The carriage 61, also called steel shoe, has a two-part design. One carriage part has a foot 62, on which a semicircular shell 63 is arranged. This semicircular shell 63, installed via the insulation, is bolted at connection points to a second, semicircular shell 64, which forms the second carriage part. A lower carriage part and an upper carriage part are thus obtained, which are bolted to one another in a plane extending obliquely to the vertical. As a result, the pipeline is in close contact in the lower shell part and is already fixed properly.
Pipelines for cold liquids, which are defined, in general, as liquids with a temperature below 11xc2x0 C., are provided with an insulation, which comprises an insulation layer directly surrounding the pipeline and an outer vapor barrier. The outer vapor barrier is occasionally damaged in practice, so that moisture penetrates into the insulation layer. This layer is to be replaced in this case. The carriage must also be removed from the pipeline for this purpose. The carriage itself is also subject to corrosive attacks and is therefore to be removed from time to time. Finally, it is also necessary to occasionally inspect the pipeline itself for cracks or corrosion on the pipeline, especially at the weld seams, for which purpose the insulation and along with it the carriage are again to be removed. According to the state of the art, the pipeline must be raised for this purpose in order to lift it out of the lower shell part, or the lower carriage part and the insulation must be completely destroyed. Raising of the pipeline cannot be considered in the case of pipelines for very cold liquids, which have a temperature of xe2x88x92164xc2x0 C. in the case of, e.g., liquefied natural gas (methane), because of the cold embrittlement of the steel pipe which occurs at these low temperatures. Thus, the pipeline must be put out of operation during the maintenance and inspection procedures, which is associated with considerable costs due to downtime. During the reinstallation of the prior-art carriages, the pipeline, already provided with new insulating shells according to the state of the art, is to be raised again in order to place it into the lower carriage part. As was said, this cannot be done during the running operation of the pipeline.
Another type of pipe support is used in pipelines with small pipe diameter for cold liquids. These pipe supports, which are also called pipe clamps, are shown, e.g., in the 1994 LISEGA Katalog Rohrschellen Rohrlager [1994 LISEGA Pipe Clamps and Pipe Supports Catalog-Tr.Ed.]. These pipe supports comprise two carriage parts, which are connected to one another at connection flanges and between which the pipeline is braced directly by means of bolts without the interposition of an insulation. One of the connection flanges is arranged, when viewed from a base plate on which the pipeline is supported vertically toward the central axis of the pipeline, exactly under the pipeline. The pipe clamps form a heat bridge here, because they are clamped on the pipelines directly without the interposition of an insulation. These pipe clamps have been known for a long time. However, they are not suitable for use as supports of the type mentioned in the introduction.
Furthermore, carriages for supporting pipelines, which comprise a plurality of carriage parts, have been known from DE-GM 1 984 394, DE 299 13 157 U1, DE-AS 2 053 949 and U.S. Pat. No. 4,858,861, where the carriage parts can be connected to one another with a connection flange, which is arranged exactly under the pipeline. These carriages correspond in this respect to the pipe supports shown in the 1994 LISEGA Katalog Rohrschellen Rohrlager.
Based on this, the basic object of the present invention is to improve a support of the type mentioned in the introduction such that it can be removed and supported in a simplified manner even during the running operation of the pipeline. Furthermore, another basic object of the present invention is to provide a process for supporting or mounting such supports.
To accomplish this object, the support according to the present invention is characterized in that when viewed from a base plate on which the pipeline is supported vertically to the central axis of the pipeline, one of the connection flanges is arranged exactly under the pipeline and that the carriage parts have guides for receiving guide tools for supporting the carriage.
The process according to the present invention is characterized in that the carriage parts are offset laterally next to the pipelines and are then moved to the pipeline by means of guide tools and are finally connected to one another.
Carrying out the process according to the present invention becomes possible only due to the construction of the support according to the present invention. The carriage parts can be brought to the pipeline laterally, i.e., in the plane of the base plate and connected, specifically bolted to one another here. Any change in the position of the central axis of the pipeline, especially the raising of the pipeline, are avoided as a result. The carriage can thus be supported and removed during running operation even in the case of pipelines carrying very cold liquids. The supports according to the present invention can also be supported with the process according to the present invention even in the case of pipelines adjoining one another at closely spaced locations one behind another in a plurality of rows. Moreover, it is guaranteed by the guide tools that jamming of the carriage parts during supporting and consequently damage to the vapor barrier of the insulation during supporting are avoided.
In a variant, guide holes, especially separate ones, are provided as guides in the connection flanges. For example, bolts can be used as guide tools in this simple design. In this case, the guide holes should be guided on the barrel of the bolt rather than on the thread. The desired guiding properties can thus be easily achieved by a suitable coordination of the fit between the guide hole and the barrel of the bolt.
It is recommended that a temporary support be provided for the pipeline during the supporting and removal of the support according to the present invention. This temporary support comprises, according to a specific exemplary embodiment, a gallows supported above the pipeline, which has a loop each to the left and right of the support for temporarily receiving the pipeline.
The present invention will be explained in greater detail below on the basis of exemplary embodiments shown in the drawings.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.